Machine for dressing millstones.



J. KNIGHT. MACHINE FOR DRESSING MILLSTONES.

MPLHLATION FILED JULY 23. 1914.

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J. KNIGHT.

MACHINE FOR DRESSING MILLSTONES. APPLICATION FILED JULY 23. 1914.

1,146,580. Patented July 13, 1915.

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MACHINE FOR DRESSING MILLSTONES.

APPLICATION man JULY 23. 1914.

PatentedJuly 13, 1915.

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JOHN KNIGHT, 0F NEWARK, NEW JERSEY.

MACHINE FOR DRESSING MILLS'IONES.

Specification of Letters Patent.

Patented July 13, 1915.

Application filed .Tu1y23, 1914. Serial No. 852,537.

To all whom it may concern:

Be it known that I, JOHN KNIGHT, a citizen of the United States, and aresident of the city of Newark, county of Essex, and State of NewJersey, have invented a new and useful Improvement in Machines forDressing Millstones, of which the following is a full, clear, and exactdescription.

My invention relates to improvements in machines for dressingmillstones, that is for cutting the grooves in the face of a stone.

My invention is especially designed for dressing millstones such as areused in cocoa mills for grinding cocoa beans, but the in vention can beused for dressing millstones for other purposes as will appear from thedescription which follows. In cocoa mills and analogous mills, thestones are arranged in series, the first having a deeper cut in its facethan those that follow, so that the grain or bean will be coarselyground, and the following stones grind it successively finer.

In grinding fibrous material of this kind the stones dull rapidly, andit has been the usual practice, in cocoa mills at 1 least, to

dress the stones with a hand tool or chisel which is a slow process, andmoreover the dressing cannot be done so accurately by hand as bymachinery.

The object of my invention is to produce a portable dressing machinewhich. canbe set on the face of a stone, and the weight of which willhold it in place while it is being operated, and which by reason of itsportability can be adjusted manually each time a new groove is to beout. In carrying out this idea I provide a motor on the frame of theportable machine so that the whole -appa ratus is compact and can beadjusted together, and the motor will have the right relation at alltimes to the cutting parts. Furthermore I provide two cutters adapted tocut the different depth grooves on the stone faces. In cutting thedeeper grooves which must have perfectly square edges in orderto cut tothe best advantage, I provide a rotary cutter which has preferablydiamond points to do the cutting, and for the shallower grooves Iprovide a reciprocating chisel to do the cutting. Furthermore I arrangethe cutters on a carriage which can be adjusted forwardly as the grooveis out, which can be readily adjusted laterally so as to produce theright spacing between the grooves, and also provide for adjusting thethrow of the cutting chisel to regulate the depth of a groove. Thecomplete machine can be placed on the face of the millstone which is tobe dressed, can be shifted toany desired position, and by simplystarting the motor the cutting can be commenced and accurately andrapidly V carriedout.

Reference is to behad to the accompanying drawings forming a part ofthis specification, in which similar reference characters indicatecorresponding parts in all the views.

Figure 1 is a side elevation of the machine embodying my invention, thesame bemg shown in'position on a millstone. Fig. 2 is a broken plan viewpartly in section and with the rotary cutters removed, showing themachine on amillstone. Fig. 3 is a broken vertical section on the line3-3' of Fig. 2, and Fig. 4 is a detail face view of therotary cutter. I

r The machine is provided with a flat base 10 which rests onthe face ofa stone to be dressed, and which is heavy enough to prevent themachinefrom tipping over. The base constitutes a part of the frame, and at oneedge it has a cross-bar 11 projecting on a line parallel with the base,and serving to carry a thin strip or plate 12which serves as a track forthe carriage truck as hereinafter described. The plate 12 never carriesmuch weight and simply serves as a steadying means when. the roller ortruck 25 is not above the millstone, its chief function being to preventthe roller from running on the face of the stone. Rising from the baseand forming a part of the frame is a web 13 which at its upper and loweredges has inwardly extending flanges 1 1 in which longitudinalways aremade asshown by dotted lines at 15, andin these ways runs the slideplate 16 which supports the carriage, and by adjusting which thecarriage is moved back which is journaled in the plate21 which issecured to the ends of the flanges 14:, and

the screw is also connected with a fixed nut 22 in the way or recess 19,said nut being at tached to the plate 16, and thus by turning the screwthe plate 16 can be moved backward and forward. I have not shown thisstructure in detail, because it is a common means of adjusting similarparts in many kinds of machines. The screw 20 has at its front end ahand-wheel 23 by which it can be turned. To assist in supporting thecarriage 18, and to also assist in preventing the machine from tipping,I provide a leg 24 on the outer end of the carriage, and this has atruck 25 at the bottom which runs on the track or plate 12 alreadyreferred to. This arrangement is shown clearly in Fig. 1;

The carriage is adjusted laterally by.

means of a screw 26 which is mounted on the plates 17 and 16, and thisscrew conroller or truck 25 is not pushed laterally of the'track 12,because the carriage 18 is never moved far, as the machine as a whole ispushed around over the top of the millstone, and the carriage providesfor nicer adjustment. On the inner side of the carriage is a verticallymovable extension 29 which has a dovetail connection 30 with thecarriage (see Fig. 2), and this extension can be adjusted vertically bymeans of the screw 31' which is journaled in a bracket 32 (see Fig. 3)on the under side of the carriage, and the screw connects with a fixednut'33 on the back of the extension 29, so that by turning the screw theextension can be moved up and down. Thisis for the purpose of regulatingthe depth of the chisel cuts as will presently appear.

Attached to the extension 29 is a plate 34 which is bifurcated and whichat the top merges by means of the bracket arms 35 into a shelf 36 whichcarries the motor 36. This as shown is an electric motor, and ispreferably of this type, but obviously the motor can be of any approvedtype, and it moves with the extension 29 so that it always has the samerelation to the parts which it drives.

Covering the back of the plate 34 is a plate 37 which carries thebracket arm 38,

and the parts 37, 34 and 29 are secured together by bolts 39 orequivalent fastenings. Sliding in the bifurcated part of the member 34is the shank 40 of the cutting chisel 41. These parts are preferablyseparable, and can be connected in any usual or preferred manner. Theshank 40 is normally pressed downward by a spring 42 which is arrangedabove it and the tension of which can be adjusted by means of the screw43 which forms an abutment for the spring and which extends through thetop of the shelf 36. The shank 40 is raised against the tension of itsspring by the following means: In the shank is a recess 44 which engagesone end of the tripping arm 45, this being pivoted as shown at 46, andthe outer end of the arm is struck and moved downward by the camprojections 47 which are carried by the shaft 48, so that as the shaft48 revolves, the cams 47 will successively tilt the tripping arm 45 andlift the inner end of the rod so as to raise the shank 40; but when thecam passes the outer end of the arm, the spring 42 will forcibly throwdown the heavy shank 40 and chisel 41, thus making a cut in the face ofthe stone. Obviously the particular means of imparting movement to theshank 40 against its spring can be departed from without affecting the lprinciple of the invention.

The shaft 48 is provided with tight and loose pulleys 49 and 50connecting by a belt 51 with the driving shaft 52 of the m0- tor 36 Thecutting'mechanism above described is for cuttingthe shallower grooves ina millstone, but for cutting the heavier grooves in the first stone of aseries, which stone bythe-way, is exceedingly hard, a rotary cutter isnecessary. To this end the extension 29 is provided with bracket arms 53(see Fig. 1) on the lower ends of which are bearing boxes 54 for theshaft 55 which carries the rotary cutter 56. The cutter is a thin diskhaving projections 57 thereon, and these carry the diamond cutters 58which are necessary to cut the very hard stone on which the cutter isused. By reference to Fig; 4 it will be noticed that these diamondcutting points are staggered, occurring alternately on opposite sides ofsuccessive teeth 57, so that a groove is rapidly cut with perfectlystraight edges. 9

When the machine is to be used, it is placed on the millstone 59, andthe frame of the machine can be moved 'to the desired point.- Thecarriage 18 is then drawn out beyond the edge of the stone by means ofthe screw 20, and the motor is started. As the motor starts, the cutter41 or 56 as desired, will be set in operation, and the carriage is fedacross the face of the stone by means of the screw 20 above described.After a groove is cut, the carriage can be moved laterally by means ofthe screw 26, which can'be used at any time for nicer adjustment, or theframe can be moved as a whole for a general adjustment. It will be notedthat the tool itself, if the cutting chisel 41 is used, can be made tocut deeper or less deep by adjusting the extension 29 verticall in themanner already described. It wi also be noted that the driving motor hasalon the face of the millstone as desired, and that the roove cuttingcan be regulated to a nicety by means of the adjusting mechanism shownand described.

Attention is called to the fact that the machine described can be usedvery rapidlg and still do accurate work, and the rapid a justment is toa large extent owing to the construction of the frame and the arranement of the adjusting and cutting parts t ereon. By having a broad flatbase which counterbalances the framework and which can be slipped in alldirections, the operator slides the base and machine to the approximatepoint of beginning operations, and then makes his finer adjustments bymeans of the carriage which carries the cutting mechanism. This is agreat advantage as the machine as a whole can be easily moved about toan desired point.

1. A machine of the kind described comprising a frame having a flat baseserving to counter-balance the machine, and which can be moved freely ona millstone, a carriage longitudinally and laterally adjustable on theframe, cutting mechanism, a vertical ex- Gopics o! thil patent may beobtained for prising a frame havin alance the machine,

of a weight to countera carriage longitudinally and laterally adijustable on the frame, a vertically adjustable extension on thecarriage, and cutting mechanism carried by the sald extension.

3. A machine of the kind described comprisin a tract connected with thebase, a member rising from the base and having longitudinal waysthereon, a slide plate movable 1n the aforesaid ways, laterallyextending arms on the slide plate forming a trs ck, a carriage movableon the said arms, a truck connected to the carriage and running on thefirst mentioned track, and cutting mechanism 'arried by the carriage.

JOHN Currms, JAMES KNIGHT.

iive cents each, by addressing the Commissioner of Patents,

Washington, D. 0.

a portable frame having a flat base, A

